1. Field of the Invention
The present invention relates generally to ultrasonic cleaners and, more particularly, to an ultrasonic cleaner employing pulsing of the ultrasonic cleaning element.
2. Description of the Background
Ultrasonic cleaners are known which employ ultrasonic energy generating elements for producing ultrasonic energy that cleans a workpiece. The known ultrasonic cleaners have the disadvantage of having a high duty cycle. That is, the ultrasonic energy generating element, generally a Piezo device, is energized for a large percentage of the time that the cleaner is in operation. This high duty cycle results in the production of a great amount of heat, wasting energy and forcing the use of thicker and more expensive materials to dissipate this heat. In addition, the constant bombardment of the workpiece with ultrasonic energy does not provide optimum cleaning of the workpiece.
One conventional ultrasonic cleaner with such a high duty cycle has been sold by the assignee of the instant application as model number SI410. FIGS. 6(A) and 6(B) are circuit diagrams of that conventional cleaner.